Diabetes mellitus is associated with impaired reproductive performance in human beings and experimental animals. One goal of this research program is to characterize the deficits seen in male and female reproductive behaviors in diabetic rats. Because some of these behavioral deficits seem to be associated with altered binding of sex hormones, we will also examine interactions between ovarian and testicular steroids and their receptors in brain in pituitary gland in diabetic rats. There are some data which suggest that undernutrition (the lack of utilizable metabolic fuels) may be a contributing factor in the reduced reproductive capacity of diabetics. Underfed or obese human beings and animals show various reproductive dysfunctions, but little is known about the effects of these conditions on sexual behaviors. Another goal of this project is to study the effects of undernutrition and obesity on reproductive behaviors and on neural binding of sex steroids in male and female rats. The interactions between body weight (or adiposity) and reproductive function is reciprocal. Gonadal steroids have important effects on body weight (particularly body fat levels) in both sexes. A final objective of this research program is to examine the effects of sex steroids on adipose tissues, especially lipoprotein lipase activity.